Conventional heating techniques typically rely on infrared (IR) energy, convective heat, or microwave energy to heat items or cook food. One problem with the use IR or convective energy is that while it takes time to penetrate a surface, to speed up the heating process the surface may become overheated or burned. One problem with the use of microwave energy is that an item may be overheated below the surface even though the surface does not brown. As can be seen, it is difficult to control the surface temperature and the subsurface temperature with either conventional IR heating techniques and/or conventional microwave heating techniques.
Some conventional heating techniques use lasers to heat a surface. One problem with the use of lasers is that they do not penetrate the surface sufficiently for many surface-heating applications. Furthermore, lasers are not very efficient having a power conversion efficiency of about ten-percent and thus not practical for industrial applications or applications where the size of the power supply is important.
Thus there are general needs for systems and methods for improved surface heating. There are also needs for more efficient surface-heating systems and methods.